I doesn't. It's perfectly fine the way it is, especially with the focus plane coinciding with the red arrow.
I was commenting on focus stacking because backdoorhippie was asking about the legality of focus stacking in Advanced Editing, during the challenge. He specifically mentioned the this challenge.
Actually not a reference to a score but to Spinal Tap as was mentioned. Had I thought that it would I likely would have called it something else knowing that some might give it 1 or a 2 just to teach me a lesson (no - no one would do that!!). Don't get the "sharper focus" comment - it's pretty sharp as I see it. Perhaps more depth of field is what was meant.
I did do some focus stacking, but not on this one. Ultimately I liked the way this came out better than the others, and particularly how the focus line runs in the direction of the arrow to the number.
As for the camera, yes, it's an old Kodak Retina IIIc rangefinder I've had sitting around for a while - since my in-laws cleaned house and headed south. Never used it but it seems to be in working order.
Nice one. I had a similar attempt at this challenge but not as near as successful as yours. And your model is much better than mine. I like the red elements and how they stand out from the overall black grey of the camera.